ARS | Publication request: Effect of day and night temperature on the expression of male sterility of nuclear male-sterile (ms8ms8) soybean

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 20, 2012
Publication Date: August 1, 2012
Citation: Perez-Sackett, P.T., Palmer, R.G. 2012. Effect of day and night temperature on the expression of male sterility of nuclear male-sterile (ms8ms8) soybean. Euphytica. 186(3):847-853.

Interpretive Summary: Seed development is an important component in agricultural plants. The coordination of male and female development is necessary for seed production. Interruptions or delays in development may lead to sterility and prevent normal seed formation. A male-sterile, female-fertile mutant plant failed to develop hybrid seed when cross-pollinated using alfalfa leaf-cutting bees. This only happened in our Santiago, Chile, environment. Our objective was to determine the permissive environment where seed were produced as well as the environment where no seed was produced. We changed day and night temperatures and measured the number of seed on control plants (Ms8 Ms8) and on male-sterile, female-fertile plants (ms8ms8). Sterility (few self-pollinated seed) was more pronounced when night temperature was 25 °C and day temperature was between 30 °C to 35 °C. Environmentally sensitive fertility/sterility mutants have been used in crop breeding programs to produce hybrid seed. Hybrid seed gives hybrid plants, which express heterosis, and usually are more productive, higher seed yield. The differential expression between male sterility and male fertility is not sufficient to warrant large-scale production of F1 hybrid seed. However, plant breeding programs could use this system to produce small quantities of hybrid seed which would increase efficiency.

Technical Abstract: In soybean [Glycine max (L.) Merr.], an environmentally stable male-sterility system is one of the requirements to produce large quantities of hybrid seed. Observations of the nuclear male-sterile, female-fertile mutant ms8ms8 in different environments suggested that environmental conditions affected expressivity of the ms8 allele with respect to male sterility. The objective of this study was to determine the effect of day and night temperatures on the expression of male sterility of the ms8ms8 genotype. Eighteen male-sterile, female-fertile ms8ms8 plants and ten fertile siblings Ms8_ were grown in growth chambers with the following day/night temperatures regimes: 20/20, 24/18, 25/19, 25/20, 27/21, 28/25, 29/17, 29/24, 30/25, 30/30, 32/25, and 35/25 °C. Stability of the ms8 allele was affected by the different temperature regimes. Increased sterility of the ms8ms8 genotype was observed when night temperature was 25 °C and day temperature varied between 30 °C to 35 °C. Seed-set was measured as the number of self-pollinated seed per plant.